Pulp thickening and washing apparatus



1941? J. c. F. c. RICHTER PULP THICKENING AND WASHING APPARATUS Filed Oct. 8, 1937 Patented Nov. 125 1941 PULP THICKENING AND APPARATUS NT OFFICE WASHING Johan Christofler Fredrik Carl Richter, Oslo, Norway, assignor to Aktiebolaget Kamyr, Oslo,

Norway Application October 8, 1937, Serial No. 168,087 In Norway October 14, 1936 1 Claim.

With circular screen dehydrating apparatus for fiber suspensions use is ordinarily made of a prepressure roller or so-called dandy roll which is pressed against the screen cylinder and serves to dehydrate or primarily compress the layer of stufi formed on the surface of the screen cylinder. If, as known, the dandy roll is so arranged as to be partially immersed in the stuff the water expressed thereby flows back to the stuff box, particularly if the dandy roll is not constructed as a suction roller or a special part or compartment is not provided over the entire width of the stuff box through which this water can pass to the exterior.. I

The object of the invention is to provide a simple arrangement wherein the construction of the dandy roll as a suction roller or the provision of a special part on the stuff box is unnecessary.

According to the invention this is accomplished in that the dandy roll immersed partially in the stuff, is packed ofi at one or both ends, at full diameter, by the side wall or side walls of the stud box and is passed through, for example, by the use of the well known sliding packing.

An exemplary embodimentof the invention is shown on the accompanying drawing.

Fig. l is a diagrammatic cross section.

Figs. 2a and 2b are diagrammatic axial sections through the screen cylinder and the dandy roll on lines AA and 3-3 of Fig. 3, and

Fig. 3 is a diagrammatic plan view.

As shown on Fig. 1,'the dehydrating apparatus consists in the usual manner of a stufi box I, in which a rotating, rigidly Journalled, screencloth covered cylinder 2, with or without a suction device, is disposed.

Mounted adjacent cylinder 2 is the movably journalled dandy roll 3 which is immersed partially in the stud and is pressed by a spring or other equivalent device against cylinder 2.

The dandy roll 3 and the cylinder 2 are, in the manner known for screen cylinders, fitted in the roller at i3.

end of the dandy r011 for rotation therewith and providing members I8 mounted on the stuff box I fitting into the member I! with a fluid-tight fit while at the same time providing suificient clearance between the bottom of the channel members andthe edges of the members I8 to permit movement of the dandy roll tra sverse to its longitudinal axis.

As shown by the exemplary constructions, the cylinder 2 and the roll 3 can 'be driven by the same shaft 4, which is connected with the cylinder 2 through a worm drive 5, while the dandy roll 3 oscillatably journalled on the arms 6 is driven through a gear drive from the gear I. which is journalled coaxially with the rotational axis of the arms 6.

The stuif box I is fed in the usual manner from an inlet 8 having the usual overflow or by a pump. The water expressed from the layer of stuff I 0 passes into the interior of the screen cylinder and the'dandy roll and flows oiT at one or, as shown on Figs. 2a and 2b at both sides. while the layer of stufl is detached or loosened from the screen cylinder by a guide surface I I. A spraying tube I claim:

A circular screen dehydrating apparatus for fiber suspensions such as cellulose wood cutting or the like comprising a stuff box, a screen cylinder located in said stuff box, a dandy roll mounted for movement toward and away from said screen cylinder, cooperating with said screen cylinder and partially immersed in the suspension in said stuiT box, said dandy roll and screen cylinder extending through the side walls of said stuff box,

side walls of the stufi box I by means of pack ings 9 disposed at the periphery. The packings 9 for the dandy roll 3 are constructed sothat they permit sufiicient freedom of movement for the roller 3 to exert the necessary elastic resilient pressure action. This is accomplished by providing a channel member I! mounted upon each packings encircling the entire outer diameters of said roll andcylinder at an end thereof, so that water passing into said dandy roll may pass freely ofi laterally through an open end, said packing encircling said dandy roll permitting movement of said roll transverse to the axis thereof and said packing comprising a cooperating channel member and a member extending intosaid channel member in liquid-tight relationship with sufli cient clearancebetween the bottomof said channel member and the other member to permit said transverse movement of said roll.

J OHAN CHRISTOFFER FREDRIK CARL RICHTER.

is shown at I2 and a pressure 

